[Tex/LaTex] change the dot to a colon after Proof in amsthm

Question

I want to write Proof: in front of a proof instead of Proof. How may I achieve this?

Here is a MWE for the set up I have now:

\documentclass{article}
\usepackage{amsthm}
\begin{document}
\begin{proof}
\end{proof}
\end{document}

Answer 1

amsthm uses \@addpunct{.} to put the period. You can patch the \proof using xpatch to replace dot by :

\documentclass{article}
\usepackage{amsthm}
\usepackage{xpatch}
\makeatletter
\xpatchcmd{\proof}{\@addpunct{.}}{\@addpunct{:}}{}{}
\makeatother
\begin{document}
\begin{proof}
\end{proof}
\end{document}

If you want upright : use this:

\makeatletter
\xpatchcmd{\proof}{\@addpunct{.}}{\normalfont\,\@addpunct{:}}{}{}
\makeatother